If the piece is a : "Colt Model 1903, hammerless, 32acp" Then the serial # 221838 was produced in the year 1916. This is according to "Colt's dates of manufacture" by R.L. Wilson.
No way to answer without a serial number.
Found a Colt 1903 hammerless with that serial number made in 1917.
1917
about 1908
1908,
about 1909
1920
The date of manufacture of Colt 1903 Hammerless .32 is 1916.(193000-234999)
The 1903 Colt Hammerless .32 with serial # 137295 was manufactured in 1912. about 1913
made about 1920...........
made about 1943.......
1951